Goblin Slayer is a manga adaptation, about an experienced silver rank adventurer who only accepts quest on hunting Goblins.
In this anime Goblin Slayer is always the hot topic due to his personality about accepting quest that concerns hunting Goblins he doesn't mind if the compensation is cheap as long as he can hunt Goblins, he is okay with that.

Due to this quest compensation/payments Goblin Slayer can't afford to buy good quality armor and weapons like others do. Goblin Slayer preference/choice of armor and weapons is also wise. He doesn't like outstanding gears because it might get him in trouble during his mission he also prefer uncleaned armor/gears so that Goblins with sensitive nose will not detect his presence immediately. About his weapon since some dungeon is very small he always use a disposable short sword or any weapons that he can freely swing in the dungeon. As a result it makes him look very poor and unfit for his rank.

Goblin Slayer fighting style is tactician and merciless. He always use whatever is there to get an advantage in killing Goblins. Like putting up a traps, burning the whole dungeon, using a priest holy barrier to suffocate the Goblins etc.

This anime main genre can be "Dark" since most of the victims here including the Goblins are being killed merciless and very cruel way.